1.      Navigate to Communities > Special Events > Friends Asking Friends > Kintera Thon.
2.      Hover over the event
3.      Click on Website Info.
4.      Click on 'Image and Text Library for Page Customization' 
5.       Select Group Page Library from the drop down box.
6.      Enable the check list 'Allow group leader to add an image (such as a logo) and text to the main group page.'
7.      Click on Save.
8.      Go back to Webinfo Checklist and click Publish the event now.

Company leaders will now be able to upload the image to company thon page.